2024-2025 La Nina

[jm1220]

Just now, George001 said:

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

Northerly winds can get it done in a storm here since the air would come from inland New England. When we have any easterly component off the water it typically kills it unless somehow we have a cold enough preceding airmass. Water is too warm until late in the month. For the Boston area and SE New England same problem. 

[40/70 Benchmark]

3 minutes ago, mitchnick said:

Cfs2 has been cooling the last  week, but I  assume it's too cool. If the trend continues, an updated forecast....err, guess may be needed. Lol

Eh...I have learned my lesson on that. In order to adjust too much colder, I'd need to see the whites of the weenie after having my ass handed to me by Bluewave's pee pee pool two years running.

[michsnowfreak]

4 minutes ago, George001 said:

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

It goes without saying that the 2nd half of December is better than the 1st half, climo-wise, just about anywhere. But I will say that every year is different. Last year we had snowy trick or treating and a bare Christmas lol. We have had years where the first half of December is a winter wonderland then no snow for Christmas. And, more recently, we have had years where December sucks overall but snowy weather arrives just in time for Christmas (2020, 2022).

[40/70 Benchmark]

3 minutes ago, jm1220 said:

Northerly winds can get it done in a storm here since the air would come from inland New England. When we have any easterly component off the water it typically kills it unless somehow we have a cold enough preceding airmass. Water is too warm until late in the month. For the Boston area and SE New England same problem. 

NE wind often will often even kill me that early...need it like NNE.

[brooklynwx99]

November has looked very warm country wide for months now… analogs have been very emphatic about that

I don’t think it being that warm has any unknown impact on the winter. seems like things are going according to plan 

[binbisso]

32 minutes ago, brooklynwx99 said:

November has looked very warm country wide for months now… analogs have been very emphatic about that

I don’t think it being that warm has any unknown impact on the winter. seems like things are going according to plan 

I'm a little skeptical of the very warm to historic warm November at least here in the east. The first 3 days look very warm however the operational and ensembles are now showing a ridge out west and a trough in the east thru the 10th. We look to go neutral nao/ao and +pna and possibly 8 thru 3 mjo. Maybe the second half torches but I'm not seeing that for the first half of November att

[binbisso]

@ brooklynwx99 not saying you are calling for a very warm November but many others have 

[brooklynwx99]

1 hour ago, binbisso said:

@ brooklynwx99 not saying you are calling for a very warm November but many others have 

I think most of the heat will be focused in the Plains and Midwest but it will get pushed into the Northeast at times

[michsnowfreak]

1 hour ago, binbisso said:

I'm a little skeptical of the very warm to historic warm November at least here in the east. The first 3 days look very warm however the operational and ensembles are now showing a ridge out west and a trough in the east thru the 10th. We look to go neutral nao/ao and +pna and possibly 8 thru 3 mjo. Maybe the second half torches but I'm not seeing that for the first half of November att

 

15 minutes ago, brooklynwx99 said:

I think most of the heat will be focused in the Plains and Midwest but it will get pushed into the Northeast at times

A mild November is one thing, but I sure don't see historic warmth.

[bluewave]

4 hours ago, George001 said:

Yeah the lower terrain of the mid Atlantic needs a lot of help in December. Even my area December climo kinda sucks the first half of the month

It’s funny that the snowfall climo has actually been better December 1st through 17th since 2011 in NYC than later in the month. NYC hasn’t had a decent late December snowstorm since the Boxing Day blizzard in 2010. My guess is this is related to the warm up we have been getting every year during the 2nd half of the month since 2011. High temperatures of 55+ have been very reliable from the December 17th through 25th.
 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending snowfall 12-01 to 12-17

2023-12-17	T	0
2022-12-17	T	0
2021-12-17	T	0
2020-12-17	10.5	0
2019-12-17	1.8	0
2018-12-17	T	0
2017-12-17	7.0	0
2016-12-17	3.2	0
2015-12-17	0.0	0
2014-12-17	1.0	0
2013-12-17	8.6	0
2012-12-17	0.0	0
2011-12-17	0.0	0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending snowfall 12-18 to 12-31

2023-12-31	0.0	0
2022-12-31	T	0
2021-12-31	0.2	0
2020-12-31	T	0
2019-12-31	0.7	0
2018-12-31	T	0
2017-12-31	0.7	0
2016-12-31	T	0
2015-12-31	T	0
2014-12-31	T	0
2013-12-31	T	0
2012-12-31	0.4	0
2011-12-31	0.0	0

 

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending max temp December 17th through 25th

2023-12-25	62	0
2022-12-25	58	0
2021-12-25	60	0
2020-12-25	61	0
2019-12-25	57	0
2018-12-25	61	0
2017-12-25	55	0
2016-12-25	58	0
2015-12-25	72	0
2014-12-25	62	0
2013-12-25	71	0
2012-12-25	56	0
2011-12-25	62	0

[qg_omega]

1 hour ago, michsnowfreak said:

 

A mild November is one thing, but I sure don't see historic warmth.

This year has been the warmest on record

[bluewave]

On 10/22/2024 at 8:08 AM, GaWx said:

What about 2020-1? It was an +EPO dominant La Niña: it had 47 +EPO, 32 neutral EPO, and only 11 -EPO days. DJF had an avg daily EPO way up at +60, a solid +EPO avg for a 90 day period:

https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt

Edit: Also, what about 2007-8? It was also +EPO dominant. It had this breakdown for # of days: 50 +EPO, 21 neutral, and 20 -EPO. It also averaged ~+60 over the 91 days.

 Edit: I consider a -50 to +50 individual day to be neutral EPO.

The actual +EPO 500 mb vortex near Alaska was pretty was pretty weak in 20-21. It was more of a +WPO Bering Sea low which cominbed with the +PNA at times and the -AO for a mild but snowy winter. 19-20 had a stronger +EPO vortex near Alaska which is why the winter was so mild and snowless combined with the +AO. Our last +EPO dominant 500 mb vortex winter during a La Niña was 2011-2012. 

 

 

[snowman19]

The actual +EPO 500 mb vortex near Alaska was pretty was pretty weak in 20-21. It was more of a +WPO Bering Sea low which cominbed with the +PNA at times and the -AO for a mild but snowy winter. 19-20 had a stronger +EPO vortex near Alaska which is why the winter was so mild and snowless combined with the +AO. Our last +EPO dominant 500 mb vortex winter during a La Niña was 2011-2012. It was a great example of a winter when even though there was a ridge over the Western US and Vancouver it was still wam coast to coast. So it shows that we can be warm and relatively snowless in the East even when there isn’t a deep trough digging into the West. 



 


 

You were right, didn’t take long for the +AMO look to come back. And the dry period since this fall has been astounding, when you compare it to other dry -PDO’s:

[bluewave]

On 10/20/2024 at 2:46 PM, GaWx said:

 Thanks for mentioning this. Because of what you said I was curious enough to go through the dailies. The upcoming ~10/23 peak won’t be just one of the strongest +AOs on record in Oct. It will be THE strongest Oct +AO peak on record and by a large margin:

 The current strongest Oct on record (back to 1950) is the 3.754 of 10/24/2008, which is about to be exceeded by ~1+!

 Strongest Oct +AO peaks back to 1950:

3.754 10/24/2008
3.560 10/6/1994
3.425 10/27/2003
3.379 10/10/2022
3.371 10/30/1983
3.294 10/31/1978
3.184 10/24/1989
3.078 10/20/1954
3.037 10/10/2001
3.009 10/17/1986

 

 Since 1950, the only AO peaks exceeding +4.75 have been during Dec-March:

5.078 1/20/1957
4.917 3/16/1968
5.040 12/2/1979
4.800 12/5/1979
5.582 1/14/1989
5.147 2/9/1990
5.991 2/26/1990
5.245 1/14/1993
4.909 1/21/1993
5.588 3/8/2015
5.910 2/10/2020
6.073 2/21/2020
5.536 3/11/2021

 (Note that the very highest peaks (6 of them at 5.5+) were almost all within Feb 10th-Mar 11th.)

 So with all of the +4.75+ peaks back to 1950 in Dec-Mar up til now, this is even more evidence of how anomalous the upcoming +AO peak will be! Even Nov has yet to have one at +4.75+ with its highest being the +4.544 of 11/2/1978. (Only Novs with a peak of +4+ were 1978, 1994, and 2013.)

If these preliminary daily AO values hold, then this will be the first 7+ sigma AO swing outside of the December to April period in around a month or less. The lowest reading back on 10-7-24 was -2.445 rising to +4.795 on 10-23 for a +7.240 sigma swing. 4 out of the top 5 greatest AO swings occurred since 2005. So this goes to how amplified  and volatile the AO index has become in recent years. 
 

Greatest AO swings on record in around a month or less since 1950 and the date on which the maximum difference from low to high or high to low occurred with the numerical value of the swing

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.daily.ao.nao.pna.aao.gdas.120days.csv
 

https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.index.b500101.current.ascii

 

#1……+10.790……3-11-21

#2…...+9.401…….1-16-16

#3……+9.256……3-2-56

#4……+9.039……4-21-13

#5……+8.522……1-25-05

#6…...+8.462…..1-15-77

#7…….+8.268….3-16-68

#8…….+7.793….2-25-01

#9…….+7.731….3-23-86

#10……+7.720…2-4-11
 

#11……+7.641…..3-5-70

#12…..+7.502…..1-19-85

#13……+7.387….3-20-78

#14……+7.240….10-23-24

#15……+7117……1-23-52

#16…..+7.066…1-24-08

#17……+7.043…3-19-15

#18……+7.038…2-10-76

 

 

 

[Stormchaserchuck1]

22 minutes ago, bluewave said:

If these preliminary daily AO values hold, then this will be the first 7+ sigma AO swing outside of the December to April period in around a month or less. The lowest reading back on 10-7-24 was -2.445 rising to +4.795 on 10-23 for a +7.240 sigma swing. 4 out of the top 5 greatest AO swings occurred since 2005. So this goes to how amplified  and volatile the AO index has become in recent years. 

Usually happens during more -AO regimes

[Eduardo]

19 hours ago, bluewave said:

It’s funny that the snowfall climo has actually been better December 1st through 17th since 2011 in NYC than later in the month. NYC hasn’t had a decent late December snowstorm since the Boxing Day blizzard in 2010. My guess is this is related to the warm up we have been getting every year during the 2nd half of the month since 2011. High temperatures of 55+ have been very reliable from the December 17th through 25th.
 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending snowfall 12-01 to 12-17

2023-12-17	T	0
2022-12-17	T	0
2021-12-17	T	0
2020-12-17	10.5	0
2019-12-17	1.8	0
2018-12-17	T	0
2017-12-17	7.0	0
2016-12-17	3.2	0
2015-12-17	0.0	0
2014-12-17	1.0	0
2013-12-17	8.6	0
2012-12-17	0.0	0
2011-12-17	0.0	0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending snowfall 12-18 to 12-31

2023-12-31	0.0	0
2022-12-31	T	0
2021-12-31	0.2	0
2020-12-31	T	0
2019-12-31	0.7	0
2018-12-31	T	0
2017-12-31	0.7	0
2016-12-31	T	0
2015-12-31	T	0
2014-12-31	T	0
2013-12-31	T	0
2012-12-31	0.4	0
2011-12-31	0.0	0

 

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending max temp December 17th through 25th

2023-12-25	62	0
2022-12-25	58	0
2021-12-25	60	0
2020-12-25	61	0
2019-12-25	57	0
2018-12-25	61	0
2017-12-25	55	0
2016-12-25	58	0
2015-12-25	72	0
2014-12-25	62	0
2013-12-25	71	0
2012-12-25	56	0
2011-12-25	62	0

The Torchmas spirit we have all come to expect.  Definitely a noticeable trend.

[PhiEaglesfan712]

Amazing how we were able to get such a warm and virtually snowless month in December 2014, despite every warning sign flashing a very cold and snowy winter. Definitely the outlier month of that winter. JFM 2015 was the coldest JFM since 1978, beating out JFM 2014.

[bluewave]

The MJO activity in MJO 5 is unusually strong for weaker La Niña this month. The latest RMM index is closer to 2020, 2017, and 2010 than 2022, 2021, 2016, and 2011. Whether we use the ONI or RONI this fall so far is closer to the weaker La Niña years like 2016. But for some reason we are still getting the stronger October MJO response which preceded the better La Niña winters. These Decembers like 2020, 2017, and 2010, had more of a mismatch pattern where the December patterns were snowier and in some cases colder like 2017 and 2010. Since we are getting this divergence between the strength of the La Niña and early MJO response not really sure what to make of it yet. Since our best La Niña winters were actually the stronger ones of the groupings and not the weaker ones. Plus there is no guarantee that this indicator will continue to work as it did in the past. As always, we may just have to wait until December actually gets underway in order to know for sure. Especially since there are other indicators signaling the potential for above to potentially well above normal temperatures and below average snowfall in NYC.

It’s based on the MJO RMM amplitude and VP anomalies in phase 5-6 during La Niña Octobers since 2010. The stronger October MJO responses had better winters in NYC relative to the other La Ninas in the multiyear event group. Those stronger MJO 5-6 Octobers also had the more robust peak La Niña ONIs from fall into winter of the multiyear groups.  All the La Niña winters around NYC since 11-12 have averaged warmer than normal. But even the warmer than average 17-18 and 20-21 winters had better snowfall than the other years in the multiyear group.

In addition, we haven’t had any cold neutral ENSOs in the -0.1 to -0.5 peak range with a strong -PDO since 2010. So not sure how the relationship would work for any year with the official CPC ONI not getting colder than -0.5. The other thing to consider is that we don’t know how long this relationship will continue to work it.

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

 

Multiyear La Niña groupings below with peak MJO 5-6 strength and the peak ONI from the fall into winter…….Strongest October MJO 5-6 and La Niña ONI leading to best NYC winters of the multiyear group bolded
 

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

October 2024….Phase 5 peak +2.762…ONI….latest weekly only -0.3

 

October 2022…Phase 6 peak +2.177…..ONI….-1.0

October 2021….Phase 5 peak +2.087….ONI….-1.0

October 2020…Phase 5 peak +2.818….ONI…..-1.3

 

October 2017….Phase 6 peak +3.353….ONI….-1.0

October 2016….Phase 5 peak +1.800….ONI….-0.7

 

October 2011….Phase 6 peak +1.674….ONI….-1.1

October 2010….Phase 5 peak +2.880…ONI…..-1.6 

[40/70 Benchmark]

58 minutes ago, bluewave said:

The MJO activity in MJO 5 is unusually strong for weaker La Niña this month. The latest RMM index is closer to 2020, 2017, and 2010 than 2022, 2021, 2016, and 2011. Whether we use the ONI or RONI this fall so far is closer to the weaker La Niña years like 2016. But for some reason we are still getting the stronger October MJO response which preceded the better La Niña winters. These Decembers like 2020, 2017, and 2010, had more of a mismatch pattern where the December patterns were snowier and in some cases colder like 2017 and 2010. Since we are getting this divergence between the strength of the La Niña and early MJO response not really sure what to make of it yet. Since our best La Niña winters were actually the stronger ones of the groupings and not the weaker ones. Plus there is no guarantee that this indicator will continue to work as it did in the past. As always, we may just have to wait until December actually gets underway in order to know for sure. Especially since there are other indicators signaling the potential for above to potentially well above normal temperatures and below average snowfall in NYC.

It’s based on the MJO RMM amplitude and VP anomalies in phase 5-6 during La Niña Octobers since 2010. The stronger October MJO responses had better winters in NYC relative to the other La Ninas in the multiyear event group. Those stronger MJO 5-6 Octobers also had the more robust peak La Niña ONIs from fall into winter of the multiyear groups.  All the La Niña winters around NYC since 11-12 have averaged warmer than normal. But even the warmer than average 17-18 and 20-21 winters had better snowfall than the other years in the multiyear group.

In addition, we haven’t had any cold neutral ENSOs in the -0.1 to -0.5 peak range with a strong -PDO since 2010. So not sure how the relationship would work for any year with the official CPC ONI not getting colder than -0.5. The other thing to consider is that we don’t know how long this relationship will continue to work it.

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

 

Multiyear La Niña groupings below with peak MJO 5-6 strength and the peak ONI from the fall into winter…….Strongest October MJO 5-6 and La Niña ONI leading to best NYC winters of the multiyear group bolded
 

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

October 2024….Phase 5 peak +2.762…ONI….latest weekly only -0.3

 

October 2022…Phase 6 peak +2.177…..ONI….-1.0

October 2021….Phase 5 peak +2.087….ONI….-1.0

October 2020…Phase 5 peak +2.818….ONI…..-1.3

 

October 2017….Phase 6 peak +3.353….ONI….-1.0

October 2016….Phase 5 peak +1.800….ONI….-0.7

 

October 2011….Phase 6 peak +1.674….ONI….-1.1

October 2010….Phase 5 peak +2.880…ONI…..-1.6 

I figured we would see that strong MJO pulse this month. I've been implying that in our exchanges. La Nina itself is meager, but the baseline is not.

[bluewave]

28 minutes ago, 40/70 Benchmark said:

I figured we would see that strong MJO pulse this month. I've been implying that in our exchanges. La Nina itself is meager, but the baseline is not.

There is so much Pacific SST warmth west of the Dateline this fall that it’s driving the baseline much more than the meager ENSO region cooling. 

[George001]

Remember about a week ago our discussion on the SAI index? It has tailed off recently and is around average, so looks like the whole issue of how relevant rapid SAI index would be is going to be a non issue after all. What is interesting is I did some very basic research on years with similar characteristics to this fall (warm centered out west, bone dry in the east) and the results are quite interesting. The list of years is not as Nina dominant as I thought it would be. The MJO pulse going on right now though is very much reflective of a La Niña background state (As Bluewave pointed out, it actually matches the stronger Nina’s, not the weaker ones we have seen over the last 15 or so years). Perhaps the composite of years similar to the November pattern will be more Nina dominant. Won’t know for sure until mid-late November or so.

[GaWx]

14 hours ago, bluewave said:

The actual +EPO 500 mb vortex near Alaska was pretty was pretty weak in 20-21. It was more of a +WPO Bering Sea low which cominbed with the +PNA at times and the -AO for a mild but snowy winter. 19-20 had a stronger +EPO vortex near Alaska which is why the winter was so mild and snowless combined with the +AO. Our last +EPO dominant 500 mb vortex winter during a La Niña was 2011-2012. 

 

 

2019-20 # of days: 58 +EPO, 25 neutral EPO, 8 -EPO; avg daily EPO +80

2020-1: 47 +EPO, 32 neutral, 11 -EPO; avg daily EPO +60

 So concurs with stronger +EPO in 2019-20 vs 2020-1 although 2020-1 still pretty +EPO dominant 

[40/70 Benchmark]

3 hours ago, bluewave said:

There is so much Pacific SST warmth west of the Dateline this fall that it’s driving the baseline much more than the meager ENSO region cooling. 

Completely agree. 

[snowman19]

@Gawx

[snowman19]

12 hours ago, George001 said:

Remember about a week ago our discussion on the SAI index? It has tailed off recently and is around average, so looks like the whole issue of how relevant rapid SAI index would be is going to be a non issue after all. What is interesting is I did some very basic research on years with similar characteristics to this fall (warm centered out west, bone dry in the east) and the results are quite interesting. The list of years is not as Nina dominant as I thought it would be. The MJO pulse going on right now though is very much reflective of a La Niña background state (As Bluewave pointed out, it actually matches the stronger Nina’s, not the weaker ones we have seen over the last 15 or so years). Perhaps the composite of years similar to the November pattern will be more Nina dominant. Won’t know for sure until mid-late November or so.

So we are going to end up with a perfectly normal October SAI. Not that it mattered anyway. We spoke about it before but 14-15 rendered the entire high SAI = -AO and -NAO argument bogus. A record high SAI in 2014 and one of the most positive AO and NAO winters on record

[GaWx]

3 hours ago, snowman19 said:

@Gawx
 

 That was referring to yesterday’s SSN, which turned out to be the highest for any day since August 12th! So far today, it is even a good bit higher than that!

[bluewave]

10 hours ago, 40/70 Benchmark said:

Completely agree. 

In order for the MJO relationship to work again this year, all the seasonal models are going to have to be way off for December. The last 2 years when the MJO 5 amplitude was closer to this strong in October were 2020 and 2017. Right now none of the forecasts models look similar to those two years in December. The key to those seasons was a snowy and at times colder December around NYC with a mismatch pattern going against the La Niña and -PDO. Then the whole winter still averaged warmer than normal, but not as warm as our recent warmer La Niña winters like 16-17, and 22-23. Snowfall was much better those years. The fact that the La Niña is so weak now like 16-17 instead of the stronger years like 17-18 and 20-21 also is different  since our best La Niña winters since 10-11 have been stronger.And it was those stronger La Niña Octobers that had the stronger MJO activity. Not such a weak event having a stronger MJO October response this year.  This a reversal from 95-96 to 08-09 when the weaker La Ninas have been the better winters.

So while the seasonal models haven’t been the most reliable during recent winters, I am not ready to yet buy that there is going to be a big mismatch right out of the gate in December. Remember, the good La Niña winters start out with great frontloaded results in December and then revisit it again at some point later on. They don’t start out warm and snowless in December in NYC and then turn great later on. So I am going to view these October MJO results with caution and will need to see the the models as we get closer into December really diverge from the seasonal forecasts. Otherwise it will be a case of this winter following the weaker La Niña script with warmer and less snow December and the early October MJO indicator not working for the first time since 2010. 

[snowman19]

 That was referring to yesterday’s SSN, which turned out to be the highest for any day since August 12th! So far today, it is even a good bit higher than that!

It sure has…over 250 and climbing. There’s a chance we go over 300

[GaWx]

42 minutes ago, snowman19 said:

It sure has…over 250 and climbing. There’s a chance we go over 300

 

 

 

 

We will see about whether 300 is reached in the coming days as that is pretty rarely reached. If it were to exceed 290 on any day, it would be the highest in >20 years (not the hardest thing to do considering the prior weak cycle). We could easily top out today as nobody knows. It is high enough as it is!

*Edited due to poor wording.

 

 

[roardog]

This is a great thread but it’s funny at times. The stronger MJO rotation through 4,5 and 6 in October was talked about as a positive a couple of months ago for the East Coast in December. Now that it’s happened, the talk is how the seasonal models show nothing like the good December pattern those rotations have brought in the past. However, whenever the seasonal models show a good or decent East Coast pattern, it’s always repeated about how unreliable seasonal models are. I guess you guys just can’t win.lol